Stairway



W. A. DAVIS.

STAIRWAY.

APPLICATION FILED MAY 7. I920.

Patented Aug. 23, 1921.

1720672507 \A'MQM 'UNITED' PATENT OFFICE].

WILLIAM A. DAVIS, OF MALDEN, MASSACHUSETTS, ASSIG-NOR TO BABCOCK-DAVIS CORPORATION, 013 BOSTON, MASSACHUSETTS, A CORPORATION OF MASSACHU- SETTS.

STAIRWAY.

Specification of Letters Patent. Patented Aug. 23, 1921 Application filed May 7, 1920. Serial No. 379,493.

To all whom it may concern:

Be it known that I VVILLIAM A. DAvIs, a citizen of the United States, residing at Malden, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Stairways; and I do hereby declare the following to be a full, clear and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention relates to concrete stairs and method of manufacturing.

It is well known to those skilled in the art that concrete stairs are widely used in all types of building construction at the present time and that in actual practice these stairways are invariably made by casting the concrete on the job, that is, steel or wooden frames of the desired form are erected and the concrete is then poured and allowed to stand until properly set. This method of construction obviously entails some considerable loss of time which must elapse between the erection of the forms and the hardening of theconcrete, during which the stairway cannot be used. Under present conditions where rapidity of construction is an essential factor this becomes a serious detriment.

i111 object of the present invention is to provide a new and improved form of concrete stairway which is superior in construction to any existing forms of stairway now known and which may be easily and cheaply erected.

lVith this object in view the several features of the invention consist in certain novel features of construction combinations and arrangements of parts hereinafter described and claimed, the advantages of which will be obvious to those skilled in the art from the following description.

In the accompanying drawings illustrat ing the preferred form of the invention F igure 1 represents a side elevation of the completed stairway; Fig. 2 is a detail illustrating a section in elevation of the separate elements of the stairway and the method of supporting these elements during the assembling process; Fig. 3 is a detail showing a cross section through one of the stair treads, illustrating the manner in which the tread is clamped between the oppositely disposed supporting members.

The stairway shown in the illustrated embodiment of the invention is constructed by assembling the desired number of previously formed treads and risers between the two supporting members and thereafter drawmg the supporting members together 'to clamp the treads and risers of the stairway rigidly in assembled position. As shown clearly in the drawings, each separate element comprises a riser l0 and a tread 11 cast integrally therewith and having the usual overhanging portion 12. Each of these elements has a wire mesh screen 14 or other form of metallic reinforcement embedded therein. In addition, two positioning mem bers 16 are embedded in each element and provided with free ends 20 and 21 which project outwardly beyond the casting to engage with the supporting bolts, in the manner shown in Figs. 2 and 3. In erecting the stairway, these previously formed risers and threads are loosely supported upon throughbolts 23 which are received in openings 24 formed in supporting members 25 and 26. The supporting members may consist of channel iron previously drilled at the proper points to receive the through-bolts and loosely supported at their upper and lower ends upon the floor landings. The throughbolts are then. passed through the previously formed openings and the elements of the stairway are assembled upon the bolts, the ends of the positioning members serving to maintain them in the proper assembled position with the bottom portion of each riser seated in a recess 30 formed in the upper face of the next lower tread. After all of the elements of the stairway have been completely assembled the two supporting members 25 and 26 are drawn together by means of nuts 27 which are threadedly received on the ends of the through-bolts. This rigidly clamps the several elements of the stairway between the supporting members and holds the concrete treads and risers in position without the necessity for any further fasten- The advantages of such a method of construction must be obvious to those skilled in the art due to the fact that the concrete portions of the stairway may be cast at any convenient place however remote from the point of erection and thereafter rapidly assembled in the completed stairway without any loss of time incident to the hardening of the concrete.

The completed stairway so formed is superior in many respects to existing forms of stairway as the through-bolts supporting the individual treads prevent any possibility of failure under heavy loads and the fact that the treads and risers are formed separately permits the replacemert of any element which may become worn or unfit for use without disturbing or rebuilding the entire stairway. Furthermore, the fact that the several treads and the diagonal supports are clamped together through the medium of the through-bolts avoids the necessity of fastening the supporting members at top and bottom, permitting the entire stairway to be removed bodily, if so desired. On the other hand, if desirable, the entire stairway may be assembled outside of the building and through the use of a crane deposited in the proper position.

It will, of course, be obvious that although the illustrated embodiment of the invention shows the riser and tread of each stair as cast in a single integral piece that these risers and treads may be cast separately, if so desired, without departing from the scope of the invention.

It will be evident upon referring to Fig. 1 of the drawings, that all of the separate stair elements may be firmly held in place and interlocked with one another, the riser of the lowermost stair being seated in a recess formed in the landing and the riser of each succeeding stair being seated in a recess formed in the next lower stair tread, as indicated in Fig. 2. The recess formed in the tread face of the uppermost stair may cooperate with a corresponding shoulder formed upon the upper floor landing.

While it is preferred to employ the specific construction and arrangement of parts shown and described, it will be understood that this construction and arrangement is not essential except so far as specified in the claims, and may be changed or modified without departing from the broader features of the invention.

The invention having been described, what is claimed is:

1. A stairway comprising a plurality of substantially parallel diagonal supporting beams, a series of separate concrete stair elements located between the supporting beams and each comprising a tread member and a riser depending integrally from the front portion of the tread member, each of the tread members having a recess formed in the rear portion of the tread face to receive the lower portion of the next adjacent riser, and supporting means connected to the diagonal supporting beams and adapted to engage directly with the under portion of each tread member to support the separate stair elements from the diagonal supporting beams.

2. A stairway comprising a plurality of substantially parallel diagonal supporting beams, a series of separate concrete stair elements located between the supporting beams and each comprising a tread member and a riser depending integrally from the front portion of the tread member, each of the tread members having a recess formed in the rear portion of the tread face to receive the lower portion of the next adjacent riser, a reinforcing metallic screen embedded in each stair element and extending in the form of a right angle through the tread member and integral riser, and means connected to the diagonal supporting beams and engaging directly with the under face of each tread member to support the separate stair elements from the supporting beams.

3. A stairway comprising a plurality of substantially parallel diagonal supporting V beams, a series of separate concrete stair elements located between the supporting beams and each comprising a tread member-and a riser depending integrally from the front portion of the tread member, each ofthe tread members having a recess formed in the rear portion of the tread face to receive the lower portion of the next adjacent riser, a reinforcing metallic screen embedded in each stair element and extending in the form of a right angle through the tread member and integral riser, and through-bolts passing through the diagonal supporting beams and engaging directly with the under face of each tread member to support the separate stair elements and to clamp the stair elements and diagonal supporting beams together.

WILLIAM A. DAVIS. 

